lantern (n.) Look up lantern at
mid-13c., from Old French lanterne "lamp, lantern, light" (12c.), from Latin lanterna "lantern, lamp, torch," altered (by influence of Latin lucerna "lamp") from Greek lampter "torch, beacon fire," from lampein "to shine, give light, be brilliant" (from PIE root *lap- "to light, burn;" see lamp).

Variant lanthorn (16c.-19c.) was folk etymology based on the common use of horn as a translucent cover. Lantern-jaws "hollow, long cheeks" is from a resemblance noted since at least mid-14c.; Johnson suggests the idea is "a thin visage, such as if a candle were burning in the mouth might transmit the light."